fix(Starter): 禁用单人游戏按钮防止重复点击

在开始单人游戏时禁用按钮，避免玩家重复点击导致意外行为。同时调整UI元素的水平尺寸标志以保持布局一致。

components/Scenes/FullscreenPanels/Starter.tscn

@@ -231,6 +231,7 @@ text = "游戏模式："
 [node name="gamemodeOption" type="OptionButton" parent="content/wrapper/wrapper/start/starter/singleplayer/playConfig/gamemode" index="1" unique_id=620219949]
 unique_name_in_owner = true
 layout_mode = 2
+size_flags_horizontal = 3
 theme = ExtResource("4_lfxcn")
 selected = 0
 allow_reselect = true
@@ -272,6 +273,7 @@ text = "新手教程？"
 [node name="useTutorialBtn" type="Button" parent="content/wrapper/wrapper/start/starter/singleplayer/playConfig/useTutorial" index="1" unique_id=689654160]
 unique_name_in_owner = true
 layout_mode = 2
+size_flags_horizontal = 3
 toggle_mode = true
 button_pressed = true
 text = "观看"